Take Your Second Measurement, Build an Audio Equalizer Using NI myDAQ and LabVIEW

Overview

This document walks you through creating an NI myDAQ audio equalizer. Use the AUDIO IN jack on the NI myDAQ to acquire a stereo audio signal from an iPod or another audio player, alter the signal in NI LabVIEW software, and then output the signal to the AUDIO OUT jack on the NI myDAQ.

Table of Contents

1. Prepare to Take Your Measurement

Before beginning, make sure your software is installed and NI myDAQ hardware is configured. If you have not completed this yet, visit Setting Up Your NI myDAQ.

For this tutorial, you need your NI myDAQ with USB cable and audio cable, an iPod or another audio source, and powered speakers.

Figure 1.NI myDAQ AUDIO OUT and AUDIO IN Jacks

If you haven't already done so, connect your NI myDAQ to your computer using the USB cable. Next, use the audio cable to connect the output of the iPod or audio source to the AUDIO IN jack on the NI myDAQ. Then connect the speakers to the AUDIO OUT jack on the myDAQ.

2. Audio Equalizer VI

You can change the effect on the audio signal by sliding the volume and level sliders on the front panel.

Figure 3.NI myDAQ Equalizer VI Block Diagram

As you can see in the block diagram in Figure 3, a DAQ Assistant VI is used to acquire the audio signal from the left and right audio channels on the NI myDAQ. After the signal is acquired, it is passed to three Filter Express VIs that separate the audio channels into bass, midtone, and treble waveforms. After the signal is split up, the three audio components are multiplied by the corresponding controls on the front panel. The signals are then added together and multiplied by the volume control on the front panel. Finally, a second DAQ Assistant Express VI is used to output the final left and right audio streams to the AUDIO OUT jack.

Press Play on the iPod or another audio source. Then press the Run button in LabVIEW to run the NI myDAQ Equalizer VI. Move the sliders on the front panel to listen to the audio change.